1) Field of the Invention
The present invention relates to an ultrasonic surgical system with which a surgical medical treatment such as an incision and a blood coagulation at a target such as a living tissue is operated, applying ultrasonic vibrations.
2) Description of the Related Art
An ultrasonic surgical system with which an incision or an excision is operated on a target such as a living tissue by ultrasonically vibrating a tip of a probe that is installed to an operating instrument while blood vessels and nerve tissue and the like are preserved has conventionally been developed. The ultrasonic vibrations of the ultrasonic surgical system are realized by drive controlling an ultrasonic transducer that is installed in a handpiece. Generally, it is preferable that the ultrasonic vibrations are controlled to drive at around a resonance frequency.
An example of such an ultrasonic surgical system is disclosed in Japanese Patent Application Laid-Open No. 2000-237204. The ultrasonic surgical system executes a PLL (Phase Locked Loop) control. A frequency of a signal to drive control the ultrasonic transducer is controlled to agree with the resonance frequency by comparing a phase difference between a driving current and a driving voltage provided to the ultrasonic transducer. The ultrasonic surgical system retrieves a resonance condition by providing a resonance frequency that is detected most lately when an abnormal driving is occurred.
Moreover, an example of an ultrasonic surgical system is disclosed in Japanese Patent Application Laid-Open No. 2002-209907. The ultrasonic surgical system stores a driving current, a maximum output voltage, a control mode, a maximum load point, and a frequency lock region in a nonvolatile memory such as an EEPROM. The nonvolatile memory is embedded in a cable of a handpiece. Generation of ultrasonic frequency is controlled based on parameters stored in the nonvolatile memory when the power is just turned on, or when a load that fluctuates the resonance frequency is given.
In the field of medical treatment such as an endoscope surgical operation, an ultrasonic surgical system has been used choosing combinations of various kinds of handpieces having particular driving characteristics and various operating instruments that include probes having various shapes depending on a case. Therefore, there has been a demand for an appearance of an ultrasonic surgical system that drives various kinds of handpieces efficiently in a resonance condition with only one control system, and that outputs desirable ultrasonic vibrations from various kinds of probes. In other words, an improvement in a general versatility of the control system to the handpiece and an improvement in a general versatility of the handpiece to the probe are both required.